Forensic Science: Key Concepts and Evidence Types

Who decrypts data and recovers hidden information from digital devices?

Cyber forensics

Who can match a bullet from a crime scene to a specific weapon?

Ballistic expert

Who evaluates genetic evidence from body fluids, skin, hair roots, and tissues?

DNA analyst

Who evaluates whether a suspect is mentally ill or provides a personality profile?

Psychiatrist

Who tests body fluids and tissue samples to identify drugs or chemicals present?

Toxicologist

Who determines time of death based on insect activity on a corpse?

Entomologist

Who compares teeth to dental records to identify victims?

Odontologist

Who conducts an autopsy to determine cause, manner, and time of death?

Pathologist

What is the oldest example of forensic science dating back to the 12th century?

Fingerprints

What does the Locard Exchange Principle state?

Whenever two objects come into contact, they exchange material

Which type of evidence is more reliable: physical or testimonial?

Physical evidence

What are key facts about eyewitness testimony?

It can be unreliable, affected by stress, influenced by suggestion, and confidence does not equal accuracy

If you witness a crime, what are you more likely to remember?

The weapon (weapon focus effect)

What changes to victim identification do Jennifer Thompson and Ronald Cotton advocate for?

Improved eyewitness identification procedures such as double-blind lineups

What is responsible for most wrongful convictions?

Eyewitness misidentification

What is circumstantial evidence?

Evidence that implies a fact but does not directly prove it

What is transient evidence?

Temporary evidence that is easily lost or changed

What is conditional evidence?

Evidence produced by a specific action or the condition of the scene

What is individual evidence?

Evidence that can be linked to a single, unique source

What is class evidence?

Evidence associated with a group of items sharing characteristics

What type of evidence is an eyewitness description?

Testimonial (direct) evidence

What type of evidence is a knife?

Collectable physical evidence

What type of evidence is body temperature?

Transient evidence

What type of evidence is the position of the body?

Conditional evidence

What type of evidence is blood?

Collectable physical evidence

What type of evidence is an unlocked door?

Conditional evidence

What type of evidence is the odor of gasoline?

Transient evidence

Are fingerprints class or individual evidence?

Individual evidence

Is expert testimony physical or testimonial evidence?

Testimonial evidence

Are footprints in dust transient or physical evidence?

Transient evidence

Is hair class or individual evidence?

Class evidence

Are fibers from a blanket class or individual evidence?

Class evidence

Give an example of circumstantial evidence.

Fingerprints, fibers, bloodstains, footprints

Is a tire print with unique wear class or individual evidence?

Individual evidence

Is soil from a suspect's shoes class or individual evidence?

Class evidence

Is a torn piece of paper class or individual evidence?

Individual evidence

Are tiny shards of glass class or individual evidence?

Class evidence

Are latex gloves without fingerprints class or individual evidence?

Class evidence

Are fingerprints on glass class or individual evidence?

Individual evidence

Would a single class trait be useful on its own to identify a suspect?

No

Using the product rule, how many suspects remain if 30% have black hair and 40% wear a black jacket?

12 suspects

How many suspects remain if black hair, black jacket, and Nike shoes are combined?

3 suspects

What does the product rule show about class evidence?

Combining multiple class traits greatly narrows suspects

What crime scene step involves writing a detailed report?

Taking notes

What step includes photos, videos, and sketches?

Observing and documenting the scene

What step gives investigators an overall view of the scene?

Searching the scene

What is the written record showing who handled evidence?

Chain of custody

Why is a preliminary walkthrough done immediately?

To document transient or conditional evidence before it changes

Why must evidence be sealed separately and labeled?

To prevent contamination

Why are different search methods used at crime scenes?

Because scene size and circumstances vary

Why do crime scene technicians perform initial screening tests?

To determine what type of substance is present

What crime scene processing error occurred in the Jeffrey MacDonald case?

Failure to preserve and isolate the crime scene